Doctors use the term comorbidity to describe a condition or illness that occurs at the same time as another condition or illness. Comorbid illnesses can interact in ways that worsen both. Morbidity should not be confused with the term mortality. Morbidity means disease or illness, while mortality means death.1
Is any condition with dry eyes considered a comorbid disease?
This is where it gets tricky. You may have a condition, disease, or even take medicines that cause dry eyes. This is called secondary dry eye. Your doctor may or may not consider the condition or disease a comorbid condition. This is because not all dry eye is dry eye disease or chronic dry eye.
Some examples of conditions that may occur at the same time as chronic dry eye may include:2-22
- Kidney disease – Long-term kidney disease causes extra minerals inside the body to settle in the eyes. This causes irritation and can lead to dry eyes.
- Hashimoto’s disease – This is an autoimmune disease where the body attacks the thyroid gland. This causes decreased thyroid function (hypothyroidism). Dry eye symptoms may occur, especially in older adults.
- Lyme disease – This is a bacterial infection you can get if you are bitten by an infected tick. The disease leads to a rash, fever, headache, and feeling tired. Lyme disease may spread to the joints, heart, and nervous system. Dry eye symptoms may occur if the disease affects the nervous system.
- Chagas disease – This is caused by a parasite also known as a “kissing bug.” When this bug bites, it leaves behind waste. You can become infected if you rub the waste in your eyes or nose, the bite, or an open sore. This disease can lead to serious heart or gut problems. It can also cause eyelid swelling, which can lead to dry eyes.
- Crohn’s disease – Crohn’s disease is an inflammatory bowel disease (IBD) that can affect any part of the digestive tract. Crohn’s disease can lead to problems with vitamin absorption. An abnormally low vitamin A level can lead to dry eyes.
- Parkinson’s disease – Parkinson’s disease (PD) is a disorder that affects the nervous system. PD causes symptoms that impact a person’s ability to move (motor symptoms) such as tremor, stiffness, difficulty walking, and impaired balance. Dry eye signs with PD can be due to the disease, the medications used to treat the disease, or unrelated and caused by something else.
- Graft-versus-host disease – This is a serious and possible life-threatening complication of organ or tissue transplant surgeries. This is when your immune system attacks the newly donated tissue or organ. Dry, itchy eyes may be a sign of this condition when eye tissue is transplanted.
- Sjögren’s syndrome – This is an autoimmune disease where the body attacks its own glands that make tears and saliva. This causes dry eyes and dry mouth.
- Graves’ disease – Another thyroid disease, this condition causes thyroid eye disease and is common in those with an overactive thyroid. The eye muscles and tissue around the eye can be affected. This can lead to bulging eyes and dry eyes.
- Depression and anxiety – Symptoms of dry eye disease can affect your daily living. Studies have shown those with dry eye symptoms have an increased rate of depression and anxiety.
- Rheumatoid arthritis – Rheumatoid arthritis is a chronic disease that causes joint inflammation, pain, stiffness, and swelling. The inflammation can impact the eyes, leading to dry eyes.
- Lupus – Lupus is a chronic autoimmune disease that can affect any part of the body. Inflammation to the surface of the eye, blood vessel changes, or nerve damage can all happen with lupus.
- Conditions that are treated with diuretics or beta blockers – Diuretics and beta-blockers are drugs that are often used to manage conditions that may cause increased blood pressure or swelling. These drugs decrease the amount of fluid in the tears and can lead to chronic dry eye. Some conditions treated by these drugs include hypertension, kidney disease, liver disease, and heart failure.
- Limbal stem cell deficiency – The limbus forms the border between the surface of the eye known as the cornea and the white part of the eye known as the sclera. The cornea is always being regenerated and replaced by a stem cell supply from the limbus. In limbal stem cell deficiency, this does not occur at the same rate. This leaves the surface of the eye rough and can lead to dry eyes, irritation, and sores on the surface of the eye.
- Type 2 diabetes – Doctors are still studying why diabetes and dry eye syndrome often occur together. Studies have shown that increased blood sugar in diabetes may lead to problems with the tears, the surface of the eye, and abnormalities in blinking. All of these factors may lead to chronic dry eye.
Liver Disease – This disease is caused by long-term consumption of alcohol. This leads to damage and inflammation of the liver. Dry eye disease and symptoms of dry eye can occur with this disease.
